Hydraulic fracturing can increase the rate of production of oil and gas from low-permeability reservoirs. As is well known, hydraulic fracturing increases the permeability of reservoir rocks by opening channels through which oil and gas can travel to recovery wells. During hydraulic fracturing, a fluid is pumped under high pressure into a subterranean reservoir where it splits the reservoir rock open. A proppant, like sand, is often added to the pumped fluid and is carried in suspension into the newly formed fractures. When pumping ceases, the fractures partially close on the proppant, leaving open channels for oil and gas to flow to recovery wells.
High-pressure pumps make possible hydraulic fracturing procedures or “frac jobs.” These pumps have “fluid ends” within which a number of reciprocating plungers pressurize fracture fluids. Suction and discharge valves control fluid flow to, and from, the plungers. A valve that has too many internal projections can capture or “knock out” enough proppant to block the flow of fluid through a pump, requiring that time and effort be invested to clear the blockage—a costly undertaking. Also, these projections can create substantial pressure losses that require more energy to be expended than is necessary to perform hydraulic fracturing work.